The invention concerns a water separator for water contained in fuel. It is known to configure water separators with a water drainage device. For example, DE 600 26 724 T2 discloses a water-separating fuel filter with a water collecting chamber for separated water. Reaching a maximum filling level of the water in the water collecting chamber is detected by a sensor. A pump of the water separator then pumps the water out of the water collecting chamber.
DE 10 2010 047 354 B3 discloses a further fuel filter system. The known fuel filter system comprises a water drainage line. The fuel filter system comprises a bidirectionally closeable valve that is controllable depending on the pressure of the water drainage line.
It is moreover known to provide water separators for water contained in fuel with a float valve.
For example, DE 20 2011 104 600 U1 and DE 32 17 162 A1 disclose water-separating fuel filters. The separated water collects at the bottom of a filter housing. At this bottom, a drainage valve is arranged which in case of water collection at the bottom opens by means of a ball float.
DE 11 2010 003 359 T5 discloses a fuel filter with a float valve that prevents that fuel enters a water collecting chamber.
DE 10 2008 020 233 A1 discloses a water separator with an evaporation device. The water separator comprises a float valve at the vapor outlet in order to prevent that evaporated diesel oil can reach the environment.
U.S. Pat. No. 5,705,056 A discloses a water separator with an outlet valve. The outlet valve is opened by a float valve upon collection of water.
Finally, EP 0 060 106 A2 discloses a water separator with a drainage labyrinth. Above the drainage labyrinth a separator element is arranged and below the drainage labyrinth a water collecting chamber is arranged. In the drainage labyrinth several balls are provided in order to prevent sinking of fuel into the water collecting chamber and to accelerate sinking of the water.
In the known water separators with a float valve, separator element, water collecting chamber, and a fluidic connection between separator element and water collecting chamber are arranged serially relative to each other wherein the float valve controls the inlet to the water collecting chamber or the outlet from the water collecting chamber. Therefore, only one outflow path out of the water separator is provided for the separated water. When this one outflow path fails, for example, because the water collecting chamber is full and a maintenance signal is ignored, failure of the water separator occurs.
WO 2010/020489 A1 discloses in this context a water separator with a water collecting chamber provided at the bottom with a water outlet and at the top with a fuel outlet so that, even in case of a full water separator, the latter can continue to operate. In WO 2010/020489 A1 the water collecting chamber however operates as a separator element with calmed flow. Due to the return of fuel, a certain current is thus caused.